Detection and Characterisation of Anaplasma marginale and A. centrale in South Africa

Epidemiology of Anaplasma marginale and Anaplasma centrale infections in African buffalo (Syncerus caffer) from Kruger National Park, South Africa

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Hematobiochemical, serological, and molecular detection of Anaplasma marginale in dromedary camels (Camelus dromedarius) in Al-Najaf desert, Iraq

Background and Aim

Anaplasmosis, an underestimated disease transmitted by ticks, is widespread in ruminants, such as the Arabian camel (dromedary camel). This study aimed to examine the presence of Anaplasma marginale in dromedary camels in the Al-Hiadyia region of the Al-Najaf desert, Iraq, using serological and molecular tests. Moreover, hematological and biochemical changes in infected animals were compared with those in healthy controls.

Materials and Methods

The study was conducted on 30 healthy and 260 infected camels with severe anemia, pale mucus membranes, and progressive emaciation to investigate antibodies against A. marginale using indirect enzyme-linked immunosorbent assay, followed by polymerase chain reaction for selected positive samples targeting a specific region of A. marginale major surface protein 5 (MSP5). In addition, hematological and biochemical parameters were measured to indicate the effect of the disease on blood profile, mineral status, and liver and kidney functions.

Results

Enzyme-linked immunosorbent assay analysis and microscopic examination revealed that 115/260 (44.23%) and 87 (33.46%) camels were positive for Anaplasma spp., respectively. The MSP5 gene, which is unique to A. marginale, was amplified. The results of hematological analysis indicated a significant decrease in total red blood cells, hemoglobin, and packed cell volume and a significant increase in mean corpuscular volume in infected camels, but no difference in mean corpuscular hemoglobin concentration. Moreover, there was a significant increase in total white blood cells count, lymphocytes, erythrocyte sedimentation rate, and platelets. The results of biochemical analysis indicated a significant increase in the levels of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase, blood urea nitrogen, creatinine, and iron and a decrease in copper in infected camels. Cholesterol and triglyceride showed no significant variations between healthy and diseased camels.

Conclusion

To the best of our knowledge, this is the first molecular study to demonstrate the presence of A. marginale in dromedary camels in Iraq. The MSP5 gene is a valuable and unique diagnostic target for identifying A. marginale.

Anaplasma Species in Africa-A Century of Discovery: A Review on Molecular Epidemiology, Genetic Diversity, and Control

Anaplasma species, belonging to the family Anaplasmataceae in the order Rickettsiales, are obligate intracellular bacteria responsible for various tick-borne diseases of veterinary and human significance worldwide. With advancements in molecular techniques, seven formal species of Anaplasma and numerous unclassified species have been described. In Africa, several Anaplasma species and strains have been identified in different animals and tick species. This review aims to provide an overview of the current understanding of the molecular epidemiology and genetic diversity of classified and unclassified Anaplasma species detected in animals and ticks across Africa. The review also covers control measures that have been taken to prevent anaplasmosis transmission on the continent. This information is critical when developing anaplasmosis management and control programs in Africa.

Molecular detection and characterization of Anaplasma marginale infecting cattle, buffalo, and camel populations in southern Egypt

Anaplasmosis is a severe tickborne disease of ruminants caused by Anaplasma marginale. A. marginale is distributed worldwide and attacks erythrocytes, resulting in an increased body temperature, anemia, jaundice, abortion, and, in some cases, death. Animals infected with this pathogen become lifelong carriers. In this study, we aimed to detect and characterize A. marginale isolated from cattle, buffalo, and camel populations using novel molecular techniques in southern Egypt. In total, 250 samples (from 100 cattle, 75 water buffaloes, and 75 camels) were analyzed by PCR for the presence of Anaplasmataceae, specifically A. marginale. The animals varied in breed, age, and gender, with most showing no signs of severe disease. By species, A. marginale was found in 61 out of 100 (61%) cattle, 9 out of 75 (12%) buffaloes, and only 5 out of 75 (6.66%) camels. All A. marginale-positive samples were examined for the heat-shock protein groEL gene and, additionally, for major surface protein 4 (msp4) and major surface protein 5 (msp5) genes to enhance specificity. Phylogenetic analysis of A. marginale targeted three genes (groEL, msp4, and msp5). This study provides the first report on using three genes for A. marginale detection in Camelus dromedarius in southern Egypt and generated new phylogenetic data for A. marginale infections in camels. A. marginale infection is endemic in different animal species in southern Egypt. Screening herds for A. marginale is recommended even when the signs of anaplasmosis are absent.

Molecular detection and characterization of Anaplasma spp. in cattle and sable antelope from Lusaka and North-Western provinces of Zambia

Rickettsiales of the genus Anaplasma are globally distributed tick-borne pathogens of animals and humans with complex epidemiological cycles. Anaplasmosis is an important livestock disease in Zambia but its epidemiological information is inadequate. This study aimed to detect and characterize the species of Anaplasma present in domestic and wild ruminants in Zambia with a focus on the infection risk posed by the translocation of sable antelope (Hippotragus niger) from North-Western Province to Lusaka Province. Archived DNA samples (n = 100) extracted from whole blood (sable n = 47, cattle n = 53) were screened for Anaplasmataceae using 16S rRNA partial gene amplification followed by species confirmation using phylogenetic analysis. Out of the 100 samples, Anaplasma species were detected in 7% (4/57) of the cattle and 24% (10/43) of the sable antelope samples. Of the 14 positive samples, five were determined to be A. marginale (four from cattle and one from sable), seven were A. ovis (sable) and two were A. platys (sable). Phylogenetic analysis of the 16S rRNA partial gene sequences revealed genetic proximity between A. ovis and A. marginale, regardless of host. The detection of Anaplasma in wildlife in Zambia shows the risk of transmission of Anaplasma species associated with wildlife translocation.

Epidemiology of Ticks and Tick-Borne Pathogens in Domestic Ruminants across Southern African Development Community (SADC) Region from 1980 until 2021: A Systematic Review and Meta-Analysis

Ticks are hematophagous ectoparasites that are capable of infesting a wide range of mammals, including domestic animals, ruminants, wildlife, and humans across the world, and they transmit disease-causing pathogens. Numerous individual epidemiological studies have been conducted on the distribution and prevalence of ticks and tick-borne diseases (TBDs) in the Southern African Developing Community (SADC) region, but no effort has been undertaken to synchronize findings, which would be helpful in the implementation of consolidated tick control measures. With the aim of generating consolidated pooled prevalence estimates of ticks and TBDs in the SADC region, we performed a systematic review and meta-analysis of published articles using the PRISMA 2020 guidelines. A deep search was performed on five electronic databases, namely, PubMed, ScienceDirect, Google Scholar, AJOL, and Springer Link. Of the 347 articles identified, only 61 of the articles were eligible for inclusion. In total, 18,355 tick specimens were collected, belonging to the genera Amblyomma, Haemaphysalis, Hyalomma, and Rhipicephalus (including Boophilus) across several countries, including South Africa (n = 8), Tanzania (n = 3), Zambia (n = 2), Zimbabwe (n = 2), Madagascar (n = 2), Angola (n = 2), Mozambique (n = 1), and Comoros (n = 1). The overall pooled prevalence estimate (PPE) of TBPs in livestock was 52.2%, with the highest PPE in cattle [51.2%], followed by sheep [45.4%], and goats [29.9%]. For bacteria-like and rickettsial TBPs, Anaplasma marginale had the highest PPE of 45.9%, followed by A. centrale [14.7%], A. phagocytophilum [2.52%], and A. bovis [0.88%], whilst Ehrlichia ruminantium had a PPE of 4.2%. For piroplasmids, Babesia bigemina and B. bovis had PPEs of 20.8% and 20.3%, respectively. Theileria velifera had the highest PPE of 43.0%, followed by T. mutans [29.1%], T. parva [25.0%], and other Theileria spp. [14.06%]. Findings from this study suggest the need for a consolidated scientific approach in the investigation of ticks, TBPs, and TBDs in the whole SADC region, as most of the TBDs are transboundary and require a regional control strategy.

Mexican Strains of Anaplasma marginale: A First Comparative Genomics and Phylogeographic Analysis

The One Health approach looks after animal welfare and demands constant monitoring of the strains that circulate globally to prevent outbreaks. Anaplasma marginale is the etiologic agent of bovine anaplasmosis and is endemic worldwide. This study aimed to analyze, for the first time, the genetic diversity of seven Mexican strains of A. marginale and their relationship with other strains reported. The main features of A. marginale were obtained by characterizing all 24 genomes reported so far. Genetic diversity and phylogeography were analyzed by characterizing the msp1a gene and 5′-UTR microsatellite sequences and constructing a phylogenetic tree with 540 concatenated genes of the core genome. The Mexican strains show 15 different repeat sequences in six MSP1a structures and have phylogeographic relationships with strains from North America, South America, and Asia, which confirms they are highly variable. Based on our results, we encourage the performance of genome sequencing of A. marginale strains to obtain a high assembly level of molecular markers and the performance of extensive phylogeographic analysis. Undoubtedly, genomic surveillance helps build a picture of how a pathogen changes and evolves in geographical regions. However, we cannot discard the study of relationships pathogens establish with ticks and how they have co-evolved to establish themselves as a successful transmission system.

Distribution and prevalence of ticks and tick-borne pathogens of wild animals in South Africa: A systematic review

Ticks are significant ectoparasites of animals and humans. Published data indicate that most vectors that transmit livestock and human pathogens in sub-Saharan Africa, are native to the region and originate from wild animals. Currently, there is a paucity of information on the role of wild animals on the epidemiology of zoonotic tick-borne pathogens in South Africa. This systematic review focuses on the distribution of ticks and prevalence of tick-borne pathogens in different wild animals in South Africa to identify potential reservoir hosts and possible hotspots for emergence of novel tick-borne pathogens. Following several screening processes, 38 peer-reviewed studies published from 1970 to 2021, were deemed eligible. The studies reported on ticks collected from 63 host species of 21 host families, mostly Canidae, Felidae, Bovidae and Muridae. A total of 49 tick species of nine genera, i.e. Amblyomma, Dermacentor, Haemaphysalis, Hyalomma, Ixodes, Margaropus, Nuttalliella, Rhipicentor and Rhipicephalus, were reported. Nine tick species, i.e. Amblyomma marmoreum, Am. hebraeum, Haemaphysalis elliptica, Hyalomma truncatum, I. rubicundus, Rh. appendiculatus, Rh. (B.) decoloratus, Rh. evertsi evertsi and Rh. simus were the most commonly reported. Pathogens of the genera Anaplasma, Babesia, Hepatozoon and Theileria were identified in the wild animals. This review provides more insight on the ecology of ticks and tick-borne pathogens of wild animals in South Africa and gives useful information for predicting their future spread. It also demonstrates that wild animals habour a diverse range of tick species. This level of diversity entails a similarly high potential for emergence of novel tick-borne pathogens. The review further indicates that wild animals in South Africa are sentinels of tick-borne protozoans of veterinary importance and some bacterial pathogens as most ticks they habour are known vectors of pathogens of domestic animals and humans. However, studies on potential tick-borne zoonoses are under-represented and should be included in future epidemiological surveys, especially in the light of climate change and other anthropogenic threats which might result in the emergence of novel tick-borne pathogens.

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Wild animals in South Africa harbor a wide range of tick species of veterinary and medical importance.

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Forty-nine tick species belonging to 9 genera were reported from 63 wild host species of 21 families.

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Majority of the ticks occur throughout all nine provinces of South Africa.

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Wildlife in South Africa are sentinels of tick-borne protozoans and some bacterial pathogens of veterinary importance.

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The review also emphasizes the host preference of the ticks and the pathogens they transmit.

First report regarding molecular epidemiology and novel variant identification of Anaplasma centrale in cattle from Pakistan

Anaplasma centrale (A. centrale) is an obligate red blood cell residing tick transmitted rickettsiae that has not been studied extensively for its prevalence in cattle along with its epidemiology. Aim of this investigation was to report the seasonal prevalence, phylogeny and epidemiological parameters associated with the prevalence of A. centrale in cattle breeds enrolled from District Layyah in Punjab, Pakistan. A total of 844 blood samples [Cross breed = 300, Holstein Friesian = 244, Sahiwal breed = 300)] were collected from apparently healthy cattle along with epidemiological data during 2017-18. PCR amplified 426 base pair fragment from 16S rRNA gene of A. centrale in 14.4% (122/844) of cattle. Amplified 16S rRNA partial gene sequence of A. centrale were confirmed by DNA sequencing and deposited to GenBank. Highest A. centrale prevalence was observed in spring (24%) followed by autumn (12.4%) summer (10%) and winter (7.1%) seasons. Sahiwal breed (18.3%) was most susceptible to A. centrale infection followed by cross (12.3%) and Holstein Friesian breed (12.3%). 69/844 (8.2%) of Giemsa stained cattle blood smears were also found positive for Anaplasma spp. Farms where animal use to drink pool water and farms where dogs and other dairy animals were living with cattle had higher A. centrale prevalence. Female cattle and dogs having tick burden were found associated with A. centrale infection. Hematological profile was severely disturbed in A. centrale positive cattle. It is recommended that A. centrale should be screened in cattle, in addition to A. marginale, for the effective control of tick born diseases in Pakistan.

Molecular and recombinant characterization of major surface protein 5 from Anaplasma marginale

Anaplasmosis is a tick-borne disease caused by the intracellular rickettsia Anaplasma marginale, which affects cattle and other ruminants in both tropical and subtropical regions of the world, and also causing tremendous economic losses due to decreasing livestock production. The major surface protein 5 (MSP5) of A. marginale is an immunodominant and highly conserved protein encoding by a single gene. In the present study, the complete full-length of the msp5 coding sequence of A. marginale Thailand strain was cloned and determined at a size of 633 bp. Phylogenetic analysis based on neigh-joining (NJ) method showed that the msp5 sequence Thailand strains were clearly distributed in 3^rd clade and conserved when compared with other strains. The results showed 9 haplotypes of the msp5 genes, and the entropy analysis of MSP5 amino acid sequences displayed 92 high entropy peaks with value ranging from 0.198 to 0.845 Additionally, a recombinant MSP5 of A. marginale (rAmMSP5) was over-expressed in the E. coli BL21 Star™ (DE3) host cell, affinity purified, and found in SDS-PAGE at a molecular weight of 26 kDa. The antigenicity of rAmMSP5 (26 kDa) and AmMSP5 (19 kDa) was recognized by rabbit anti-rAmMSP5 antisera and A. marginale-infected cattle sera. Both rAmMSP5 and AmMSP5 were perceived by these sera manifesting that recombinant and native AmMSP5 have conserved epitopes. Immunofluorescence technique using rabbit anti-rAmMSP5 antisera exhibited that the AmMSP5 is distributed on both the membrane and the outside of infected erythrocytes. Therefore, the recombinant MSP5 could be used for the development of immunodiagnostic assays and vaccine purposes for controlling anaplasmosis.

Genetic diversity of Anaplasma marginale in calves with anaplasmosis on farms in Minas Gerais, Brazil

The objective of this study was to identify Anaplasma marginale strains in dairy heifers from farms with a history of anaplasmosis in the northwest region of the State of Minas Gerais, Brazil. Among the examined animals of the four farms, the overall prevalence total of A. marginale was 55.7 % for gene msp5 and 36.7 % for blood smear. Thirty DNA samples (from 24 asymptomatic and six symptomatic animals) positive for A. marginale msp1α were sequenced to study genotype and strain diversity. The majority (28/30) were the E genotype, followed by C (1/30) and G (1/30). Thirteen different strains were found: α-β-F-F-F (nine animals), 13-27-27 (three animals), τ-27-18 (three animals), α-β-β- BRA1-31 (three animals), α- 22-1318 (three animals), 80-F-F- F-F (three animals), and α -22-13-13, α-β-β-Г, M-φ-φ-φ-φ-F, 42-25- 25-31, Q-Q-Q-M, B-Q-B-Q-B-M, and 16-17-F-F (one animal each). A new structure repeated in tandem was described and named BRA 1 (TDSSSASGVLSQSGQASTSSQLG). The α-β-F-F-F strain was present in all animals with acute anaplasmosis and in three animals asymptomatic. Thus, although 13 strains were observed in the animals evaluated, only the α-β-F-F-F strain was identified during occurrence of acute disease and mortality, we suggest that this strain has important pathogenicity for calves in northeastern Minas Gerais.

Seroprevalence and Molecular Detection of Bovine Anaplasmosis in Egypt

Bovine anaplasmosis is a tick-borne disease with zoonotic potential, caused by the obligate intracellular bacterium Anaplasma marginale. The disease is distributed worldwide in tropical and subtropical regions. The economic losses from anaplasmosis in animals is of significant importance because it causes severe morbidity and mortality in cattle. Recovered animals may become persistent carriers. Epidemiological information on the actual status of bovine anaplasmosis in Egypt is scarce. Thus, this study aimed to determine anti-Anaplasma antibody and DNA in serum samples using ELISA and PCR, respectively. In total, 758 bovine sera were collected from cattle farms located in 24 Egyptian governorates in 2015 to 2016. Sera were analyzed with the commercially available 'Anaplasma antibody competitive ELISA v2' kit and 'AmpliTest Anaplasma/Ehrlichia spp. real time TaqMan TM PCR. Anaplasma spp. antibodies were detected in 140 (18.5%) (CI: 15.8-21.4%) of the investigated sera by ELISA, and Anaplasma/Ehrlichia-DNA was detected in 40 (5.3%) (CI: 3.8-7.1%) of the positive sera by real time PCR. Co-detection of both Anaplasma spp. and Coxiella burnetii-specific antibodies was proven in 30 (4%) of the investigated sera. The results of this work confirm the significant prevalence of bovine anaplasmosis in Egypt. Raising awareness in decision makers of the public health, veterinarians and animal owners is required to reduce the spread of infection.

Draft Genome Sequence of Anaplasma marginale Strain Mex-01-001-01, a Mexican Strain That Causes Bovine Anaplasmosis

Bovine anaplasmosis is an arthropod-borne hemolytic disease caused by Anaplasma marginale. While only a few Anaplasma marginale strains have been reported, no Mexican strains have been reported. Due to the genetic diversity of A. marginale, the genome of the strain Mex-01-001-01, isolated in Mexico, represents a new source of information.

Report from the 'One Health' 9th Tick and Tick-Borne Pathogen Conference and the 1st Asia-Pacific Rickettsia Conference, Cairns, Australia, 27th August-1st September 2017

The 9th Tick and Tick-borne Pathogen (TTP9) Conference was held in conjunction with the first Asia Pacific Rickettsia Conference (APRC1) in Cairns, Australia from 27 August until 1 September in 2017. This MDPI Veterinary Sciences Special Issue has been dedicated to selected veterinary science articles from the conference associated with the control of animal diseases in the context of ticks and tick-borne pathogens, including Rickettsia species. The articles presented in this Special Issue include novel developments for the future control of ticks and tick-borne diseases. This editorial describes the meeting content, the plenaries, the TTP awards, the MDPI Veterinary Science Special Issue articles, and serves as a legacy report for TTP9APRC1.